Refrigeration apparatus, including a precooler



A ril 24, 1956 c. F. ALSING 2,742,767

REFRIGERATION APPARATUS, INCLUDING A PRECOOLER Filed Feb. 23, 1954 2Sheets-Sheet l W ff INVENTOR.

April 24, 1956 c. F. ALSING REFRIGERATION APPARATUS, INCLUDING APRECOOLEJR Filed Feb. 25, 1954 2 Sheets-Sheet 2 II VVENTOR.

BY s United States Patent REFRIGERATION APPARATUS, INCLUDING A PRECOOLERApplication February 23, 1954, Serial No. 411,795 8 Claims. (c1.62--117.8)

The present invention relates to a refrigeration apparatus and system ofthe type in which a precooler is employed for the heated gas which istaken directly from the compressor outlet to the precooler, and returnedfrom the precooler to the motor compressor housing for cooling themotor.

In the refrigeration systems of this type the refrigerant and entrainedoil are cooled in the precooler and some of the refrigerant iscondensed, and the oil and refrigerant are then delivered to the upperpart of the motor compressor housing where the liquid refrigeranttrickles down over the motor parts, cooling the motor, and the oil inthe form of droplets runs down to an oil sump which surrounds thecompressor in the bottom of the motor compressor housing. I

The effectiveness ofthe precooling coils of this type of the prior artis somewhat impaired because the temperature of the refrigerant andcoils drops rapidly through this coil, which is operating in a roomtemperature and heat does not radiate effectively from the precoolercoil part'which does not have a considerable difference in temperaturefrom that of the air to which the heat is transferred.

In the precoolers of the prior art the latterhalf of the tubing of theprecooler coil may be operating in an ambient or room temperature of 110degrees under the most adverse conditions, and the last part of thetubing may be at temperatures of 140 to 157 degrees, while the inletportion of the precoolermay run as high as 230 degrees F. J

One of the objects of the invention is the provision of an improvedrefrigeration apparatus including such a precooler in which all of theprecooler tubing is maintained at a temperature which is considerablyelevated above the ambient or room temperature at all times, so that allof the precooler tubing will effectively radiate and dissipate heat.

Another object of the invention is the provision of an improvedprecooler coil structure which radiates heat to the surroundingatmosphere more'efiiciently andwhich is simple in construction, sturdy,and adapted to be manufactured at a low cost.

Another object of the invention is the provision of an improved mode ofsupport for the precooler coil by means of which the precooler coil notonly dissipates heat from the refrigerant and oil emerging from thecompressor, but it also dissipates heat taken directly from the motorhousing.

Another object of the invention is the provision of an improved mode ofprecooler support on the motorcompressor housing which aids indissipating or attenuating noise from the operation of the compressor,and by means of which the precooler coil is arranged in the stream ofair which moves upward by convection from the motor compressor housing.I

Other objects and advantages of the invention will be apparent from thefollowing description and the accompanying drawings, in which similarcharacters of reference indicate similar I the sump and pump it alongwith the refrigerant for lubrireceiver 16.

parts throughout the several views.

Referring to the drawings, of which there are two sheets, accompanyingthe specification,

tern embodying the present invention;

Fig. 2 is a top plan view of the motor compressor and precooler unit; vI

Fig. 3 is a side elevational view of the motor sor and precooler unit.

The refrigeration apparatus embodying the invention preferably includesan evaporator 10, Fig. 1, which may comprise a box-like member of sheetaluminum having a bottom 11, rear wall 12, side walls 13 and 14, andshelf 15 extending from side wall to side wall.

The top is open but is closed by the top of the refrigerator liner towhich it is secured, and the front of the evaporator is closed by anevaporator door, not shown.

The evaporator may include a receiver '16,'comprising two enlargedportions 17 and 18, joined by an easy bend Fig. 1 is a diagrammatic viewof the refrigeration syscompresat 19'and mounted in a complementary slotor opening in nozzle 21, extending toward the receiver outlet 22.

From the receiver outlet a tube 23 extends along the bottom wall 11 tothe bottom of which it is secured, and the tubing is arranged sinuouslyat 24 on the bottom wall 11, by providing the straight portions 24 andthe U-shaped bends 25 and 26 joining these portions- From the bottomtubing 24, thetubing is bent upwardly at 27, on the outside ofthe endwall 13, and slopes upwardly sinuously at'28, with a plurality ofstraight portions which are joined by U-bends 29. I

At the shelf level the tubing is'turned inwardly through,

the wall at 30, and has a pluralityj'of straight portions 31 arrangedsinuously on the bottom of the shelf 15, and joined by U-shaped bends32. H I

At the rear end of the shelf the tubing emerges at 33 through thesidewall 14, and has a'single U-shaped bend 34 joining two straightportions 35;

The uppermost tubing 35 is bent at'36,'around the corner, and extends at37 along the rear wall 12to an upper part of the receiver 16, 'wherethere-n n inlet at 38 into the upper horizontal portion 17 of receiver16.

. The outlet from the receiver 16 and from the evapo' rater is at 39, atits upper horizontal end,,where a tube 40 extends into the end 41,andhasits openend 39 turned upwardly to be located above' anyliquid inthe The outlet. tube 40, which isalso the suction tube, is arranged inheat conducting relation with the capillary tube 20, coming from'the'motor compressor. The'motor compressor unit 42 comprises an outermotorhousing 43, the lower part of which 44, contains the compressor 45,which is directly connected to the shaft of the motor located in housing43. The lower part 44 of the motor housing forms an oil sump, which isin direct communication with the rest of the motor housing and which isfilled with oil surrounding the motor compressor'45, which may beimmersed in the oil.

There is an oil inlet 46 in the bottom plate of the compressor 45, sothat the compressor may draw oil from eating the compressor and motorLThe outlet of the compressor 45 is at 47, and is con nected by means ofa tubei48 with the precooler unit 49. Tube 48 extends through the wallof the motor housing 44, from the compressor outlet 47, and conductsrefrigerant in the form of a compressed heated gas with entrained oildirectly from the compressor to the precooler.

The inlet to the motor compressor is at 50, and is connected directly tothe tube 40, which also passes through the wall of the motorhousing 44and through the oil sump to the compressor.

The precooler condenser 49 may consist of a plurality of straight,vertical runs 51 of tubing joined by U-shaped bends 52, 53, at the topand bottom, and the outlet from the precooler unit 49 is at 54, wherethe precooler tubing discharges into the top of motor housing 43.

The main condenser 55 consists of a plurality of straight, vertical runs56, of tubing, connected at the top and bottom of the U-shaped bends 57,58. The inlet to the main condenser is at 59, from the top of the motorhousing 43, and the main condenser outlet is indicated at 60, where thetubing is joined to a refrigerant drier capsule 61, comprising a tubularmember provided with a filling of silica gel powder 62 between a pair ofscreens 63, 64. The outlet from the drier is at tube 20.

The main condenser may have its vertical passes joined by a multiplicityof welded heat dissipating fins or wires.

The motor compressor may be provided with diametrically opposite anglebrackets 66, resting upon cup-shaped members 67, within which there isseated one end of a spring 68, surrounding a screw bolt 69, having a nut70.

Screw bolt 69 also passes through a transverse frame member 71, whichhas its ends 72 secured to the cabinet and upon the top of which thespring 68 is seated.

The transverse frame member 71 has its central portion 73 bowedoutwardly to arch about the motor compressor housing 43, and the maincondenser coils 55 are also arranged in an arcuate arrangement about theoutside of the motor compressor 43.

At their upper ends the main condenser coils are supported by a pair ofbrackets 74, mounted on the rear of the cabinet 75, and provided with asplit rubber grommet 76, which surrounds the outermost U-bend 57 at eachside of the main condenser 55.

At their lower ends the main condenser coils 55 are clamped by aplurality of welded clips 77 to a transverse frame member 78, the ends79 of which are secured to the rear wall of cabinet 75.

The present precooler coil 49 is supported directly upon the motorcompressor housing 43, by means of a clamping band 80, comprising ametal strip which is curved over the major portion of its length from 81to 82 to fit the cylindrical outer surface 83 of the motor housing 43.

Brackets 78a with rubber grommets 78b secure the outermost coils of maincondenser 55 to the rear panel at the lower end of said coils. The maincondenser 55 and details of its support and the compressor support maybe substantially as disclosed in application Ser. No. 294,091 of HarryNadler, filed June 17, 1952, U. S. Patent N0. 2,687,625.

From the point 81 to the point 84 the band 80 is curved on a largerdiameter which provides room for the precooler coils 49 between the band80 and the cylindrical surface 83, of the motor housing 43.

At its ends the clamping band 80 has a pair of outwardly turned securingflanges 85 and 86, provided with apertures 87 for passing the screw bolt88, having nut 89.

The outlet from the precooler coils into the top of the motor housing isagain indicated at 54, and the inlet tube 48 extends directly from theprecooler 49 through the lower part 44 of the motor housing into themotor compressor outlet 47.

The motor compressor housing 43 may be arranged with the forward half ofthe motor housing 43 under the lower edge of the rear wall of thecabinet, while the rear half of the motor compressor housing 43 isdisposed rearwardly of the rear cabinet wall in the chimney, which isformed by the vertically extending passes 56 of the main condenser 55.

65, leading to the capillary Therefore, the precooler 49, which is to becarried by the motor housing 43, must be arranged on the outer half erthe motor housing 43, which is that portion below the center in Fig. 2,so that the vertical passes 51 of precooler 49 may extend verticallybehind the rear wall of the cabinet 75, which customarily has a cavityfor receiving the from half only of the motor housing 43.

This makes only half of the periphery of the motor housing 43 availablefor mounting the precooler coils, of which there are too many in theparticular system to have them all spread circumferentially on the motorhousing 43.

Therefore, one portion, 49a, of the precooler coils is arranged withonly one leg of each pair of vertical passes engaging the housing, suchas the legs 51a, while the portion 49b of the precooler 49 has both ofthe legs 51b of each U-shaped portion directly engaging the motorhousing 43.

As pointed out preliminary to the description, the precooler coils ofthe prior art had their efiiciency impaired by the fact that thetemperature dropped rather rapidly through these coils from atemperature of 230 degrees F., for example, at the precooler inlet 47,to a temperature of, for example, 140 to 157 degrees F. for the lasthalf of the tubing.

According to the present invention the precooler tubing is in heatconducting relation with the hot motor housing 43, and its heatdissipating temperature may be maintained, for example, at a minimum ofabout 173 degrees F. by the conduction of heat from the motor housing 43to the precooler 49.

From the foregoing it will be evident that it is the last half of theprecooler tubing 49, that is the portion 4911, which needs the most heatconduction to bring it up to a temperature, such as 173 degrees F, atwhich it can radiate heat efliciently to the surrounding ambienttemperature, which may be as high as 110 degrees F.

Therefore, the last portion 49b of the precooler has its vertical passesall directly engaged with the motor housing 43, and welded to the insideof the band 80, to conduct heat readily from the band to the coils andto clamp the coils against the motor housing 43 for efiicient heatconduction.

The other earlier portion 49a of the precooler 49 is arranged with itsU-shaped bends extending outwardly and with only the innermost of twolegs, indicated at 51a, between the band and the motor housing 43, wherethese two coils are again welded to the band 80.

At this inlet end of the precooler coil 49, the temperature is alreadyhigh and does not need so much heat conduction from the motor housing43, to elevate its temperature to an efiicient level for radiating heatto the air.

Therefore, there is less heat transmitting contact between the verticalpasses 51a and the band and motor housing than is true for the verticalpasses 51b. The vertical passes 51 of the precooler 49 are preferablysecured to the band 80 at the lower end of these vertical passes; andthe band 80 is preferably arranged at the upper end of the motor housingand has heat engaging contact with the motor housing 43 from the point81 to the point 82.

Thus the precooler coils 49 are supported in the air above the motorhousing 43 and are in the current of air which is produced by convectionof the air that is heated by motor housing 43.

Supporting the precooler coils 49 only at one end permits the other endsand U-shaped bends 52 to be free for vibration, which will dissipate insome measure the vibration and motor compressor noise that istransmitted to the free ends 52 of the precooler coils 49, andattenuated by the vibrating action of the precooler coils 49 on themotor housing 43.

The springs 68 may be clamped fixedly by tightening nuts 70 on cups 67and bolts 69 during shipment, but

- r the nuts are loosened before operating the system; and the springs68 are adapted to absorb vibration of the motor compressor 43 andprecooler 49.

It will thus be observed that the present refrigeration apparatusmaintains a precooler temperature throughout, which is suflicientlyelevated above the ambient temperature to radiate heat elfectively tothe surrounding air, and more heat is dissipated from the motor housingand from the refrigerant and oil in the precooler.

The result is a more efiicient motor cooling by the precoolerarrangement, and motor compressor noise is also substantially reduced.

While I have illustrated a preferred embodiment of my invention, manymodifications may be made without departing from the spirit of theinvention, and I do not wish to be limited tothe' precise details ofconstruction set forth, but desire to avail myself of all changes withinthe scope of the appended claims.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent of the United States, is:

1. In a household refrigerator, a motor compressor and precooler unitcomprising, a housing having an upper,

portion enclosing a motor, andla lower" portion forming an oil sumpcommunicating with the upper portion and surrounding a compressordirectly'driven by said motor, a precooler coil having its inletdirectly connected through the wall of the lower part of said'housing tothe compressor outlet to remove .the hot compressed gas immediately fromthe compressor, said precooler unit comprising a plurality of upwardlyand downwardly extending passes of tubing arranged parallel to eachother and joined at the top and bottom by U-shaped, tube for- Y mations,the said precooler coils being in one continuous length of tubing anddischarging into the upper part of said motor housing, all of saidprecooler coils having'their lower D -shaped portions mounted on saidmotor compressor housing in heat conducting relation with said housingto raise the temperature of said precoo ler coils by heat conductionfrom the motor housing to an elevated temperature for more efficientlyradiating heat to the surrounding air, the said precooler coils beingfixedly clamped to said motor housing at their lower ends and havingtheir upper ends free for limited vibration and dissipationof noise.

2. In a household refrigerator, a motor compressor and precooler unitcomprising, a housing having an upper portion enclosing a motor, and alower portion forming an oil sump communicating With the upper portionand surrounding a compressor directly driven by said motor, a precoolercoil having its inlet directly connected through the wall of the lowerpart of said housing to the compressor outlet to remove the hotcompressed gas immedi ately from the compressor, said precooler unitcomprising a plurality of upwardly and downwardly extending passes oftubing arranged parallel to each other and joined at the top and bottomby U--shaped tube formations, the said precooler coils being in onecontinuous length of tubing and discharging into the upper part of saidmotor housing, all of said precooler coils having their lower U-shapedportions mounted on said motor compressor housing in heatconductingrelation with said housing to raise the temperature of said precoolercoils by heat conduction from the motor housing to an elevatedtemperature for more efiiciently radiating heat to the surrounding air,the said precooler coils being fixedly clamped to said motor housing attheir lower ends and having their upper ends free for limited vibrationand dissipation of noise, the said precooler coils being arranged in twosections with the section that receives the refrigerant first from thecompressor having alternate passes clamped to the i motor housing, andthe section that receives refrigerant last from the motor compressorhaving all of its vertical passes clamped to the motor housing, so thatthe last part of the precooler tubing which needs the most heatconduction to bring it up to an efiicient radiating temperature has amaximum area in contact with said motor housing. t v

3. In a household refrigerator, the combination of an insulatedcabinethaving a back panel, a transverse frame member carried by said backpanel, and having an outwardly extending central portion for passingabout a motor compressor housing, a motor compressor having an externalhousing, spring means engaging said frame member and supporting saidmotorcompressor housing, and a precooler coil comprising a plurality ofvertical passes joined by U-shaped bends, said coils having their lower.ends secured in heat conducting relation with an upper part of saidmotor compressor housing, for maintaining all parts of the pre-coolercoil at an elevated temperature for efiiciently radiating heat from thepre-cooling coils to the surrounding atmosphere, the pre-cooler coilsbeing welded to one portion of a substantially cylindrical bandextendingabout said motor housing, the other portion of said band being securedin heat conducting relation With said motor compressor housing, the saidcoils being arranged in former and latter sections, with the lattersections having a greater heat conducting contact area between the coilsand band and motor compressor housing.

, 4. A motor compressor and pre-cooler unit comprising a housing havingan upper portion enclosing a motor and a lower portion forming an oilsump communicating with the upper portion and surrounding a compressordirectly driven by said motor, a pre-cooler coil having its inletdirectly connected through the wall of said lower part of said housingto the compressor outlet to remove the hot compressed gas immediatelyfrom the compressor, said pre-cooler unit being mounted upon andextending upwardly from said motor compressor housing in heat conducting relation with said housing to raise the temperature of saidpre-cooler coils by heat conduction from the motor housing to anelevated temperature, for eficiently radiating heat to thesurroundingair, the other end of said pre-cooler,

coils being connected to discharge into a top portion of said motorhousing, the said pre-cooler coils being welded to a metal band, and thesaid band having heat exchanging contact with substantially half of theperiphery of said motor housing, the coils engaging over substantiallythe other half of the motor housing.

5. A motor compressor and pre-cooler unit comprising a housing having anupper portion enclosing a motor and a lower portion forming an oil-sumpcommunicating with the upper portion and surrounding a compressordirectly driven by said motor, a pre-cooler coil having its inletdirectly connected through the wall of said lower part of said housingto the compressor outlet to remove the hot compressed gas immediatelyfrom the compressor, said pre-cooler unit being mounted upon andextending upwardly from said motor compressor housing in heat conductingrelation with said housing to raise the temperature of saidpre-coolercoils by heat conduction from the motor housing to an elevatedtemperature, for efiiciently radiating heat to the surrounding air, theother end of said pre-cooler coils being connected to discharge into atop portion of said motor housing, the said pre-cooler coils beingwelded to a metal band, and the said band having heat exchanging contactwith substantially half of the periphery of said motor housing, thecoils engaging over substantially the other half of the motor housing,the said coils comprising a plurality of vertical passes joined by Ubends, and said coils comprising a first portion and a second portion,the said second portion having all of the legs of said coils betweensaid band and said motor housing for more effectively raising thetemperature of the latter portion of the pre-cooling coil.

6. A motor compressor and pre-cooler unit comprising a housing having anupper portion enclosing a motor and a lower portion forming an oil sumpcommunicating with the upper portion and surrounding a compressordirectly driven by said motor, a pre-cooler coil having its inletdirectly connected through the wall of said lower part of said housingto the compressor outlet to remove the hot compressed gas immediatelyfrom the compressor, said pre-cooler unit being mounted upon andextending upwardly from said motor compressor housing in heat conductingrelation'with said housing to raise the temperature of said pre-coolercoils by heat conduction from the motor housing to an elevatedtemperature, for efiiciently radiating heat to the surrounding air, theother end of said pre-cooler coils being connected to discharge into atop portion of said motorv housing, the said pre-cooler coils beingwelded to a metal band, and the said band having heat exchanging contactwith substantially half of the periphery of said motor housing, thecoils engaging over substantially the other half of the motor housing,the said coils comprising a plurality of vertical passes joined by Ubands, and said coils comprising a first portion and a second portion,the said second portion having all of the legs of said coils betweensaid band and said motor housing for more effectively raising thetemperature of the latter portion of the pre-cooling coil, and the firstportion of said coils having alternate legs of said vertical passeslocated between the said band and motor housing for a diminishedconduction of heat from motor housing to coils in this portion.

7. In a refrigeration apparatus, the combination of an insulated cabinethaving its rear wall provided at its lower end with a cavity forreceiving substantially half of a motor compressor unit, a transverseframe member carried by said rear wall and bulging outwardly at itscentral portion to provide room for the motor compressor, a motorcompressor unit carried by said transverse frame member and havingsubstantially half of its volume in said cavity and the other halfprojecting rearwardly outside said rear wall, and a pro-cooler condensercomprising a plurality of vertical passes joined by U bends carried bysaid motor compressor on its outwardly projecting portion, the saidprecooler coils extending upwardly outside of said rear wall and abovesaid cavity by virtue of their arrangement on the outer part of saidmotor compressor housing in the stream of air moving upward byconvection from said motor compressofhousing, said pre-cooler coilsbeing welded adjacent their lower ends'to a metal band, and said bandclamping the welded portions of said coils against said motor housing.

8. In a refrigeration apparatus, the combination of an insulated cabinethaving its rear wall provided at its lower end with a cavity forreceiving substantially half of a motor compressor unit, a transverseframe member carried by said rear wall and bulging outwardly at itscentral portion to provide room for the motor compressor, a motorcompressor unit carried by said transverse frame member and havingsubstantially half of its volume in said cavity and the other halfprojecting rearwardly outside said rear wall, and a pre-cooler condensercomprising a plurality of vertical passes joined by U bends carried bysaid motor compressor on its outwardly projecting portion, the saidprecooler coils extending upwardly outside of said rear wall and abovesaid cavity by virtue of their arrangement on the outer part of saidmotor compressor housing in the stream of air moving upward byconvection from said motor compressor housing, said pre-cooler coilsbeing welded adjacent their lower ends to a metal band, and said bandclamping the welded portions of said coils against said motor housing,the said band itself engaging the motor housing over the major portionof its periphery for conducting heat through the band to said coils fromsaid motor compressor housing.

References Cited in the file of this patent UNITED STATES PATENTS2,093,471 Newill Sept. 21, 1937 2,160,018 Higham May 30, 1939 2,597,243Hubacker May 20, 1952 2,638,753 Doeg May 19, 1953 2,667,762 HornadayFeb. 2, 1954

